100BASE-TX is one of the most predominant forms of Fast Ethernet because of its capability to transmit at the rate of 100Mbps. It is an adaptation of the 100Base-T standard and is characterized by two wire-pairs which are contained in a category 5 or better cable.
Normally, category 5 cabling is designed to contain 4 pairs of wires which means that it can accommodate two 100BASE-TX wires that are connected with a wiring adaptor.
Like the 100Base-T standard, the 100Base-TX can only extend to a maximum length of 100 meters and even its configuration is the same as that of the 100Base-T in that both standards can be shared on a hub.
Using Category 5 cabling, the 100Base-TX is able to achieve a full-duplex throughput of 100 Mbps in each direction with two paired wires facing either direction. 100BaseTX standard networks are typically wired together to form a star topology in Ethernet switches or shared hubs.